Erasure-coding based dissemination protocol for mobile clouds

We present a study of a content delivery protocol exploiting a group of dynamically and intermittently connected mobile networks forming an abstract cloud service. An external user gets the content through temporary contacts with nodes of the cloud. The information to be delivered can, for example, be the electronic edition of a free daily newspaper, that users could read through their smartphones or tablets while moving. The cloud service is useful when a direct connection to the original content source is not available, or available for a limited amount of time. For the cloud service to be effective, low delivery delay and high efficiency are two very important points to achieve. To this aim, the protocol exploits erasure coding as a mean to generate a suitable amount of content redundancy. The paper reports a mathematical model that captures the effect of redundancy on the delivery delay, and showing how the optimal redundancy value can be as low as two.